But as he continues to lay the groundwork for his White House run  officially it still is in the exploratory stage  his personality is turning out to be a dual-edged sword.

On the plus side it is seen as endearing, putting him at the forefront of Republicans when it comes to being personable and telegenic.

It's hard not to like John Kasich, said Ed Gillespie, former communications director for the National Republican Party, who is advising him. He's smart, he's funny, he's compassionate and he's from the people.

But others worry that Mr. Kasich's youthful nature, including a well-publicized fondness for rock music and wearing sneakers, may come across as lacking the maturity and seasoning needed to be president.

In a president, Americans want a father figure, and John Kasich is at best an older brother, said Jack Pitney, congressional scholar at Claremont McKenna College, Claremont, Calif.

Mr. Kasich is conscious of the issue on the campaign trail.

Don't let my youthful exuberance fool you when it comes to the depth of my experience, he says as he paces in front of a room of New Hampshire voters.

On Capitol Hill, he reminds them, he annually shapes $1.7 trillion in federal spending as chairman of the House Budget Committee, a job he has held since 1995.

Indeed, Mr. Kasich does have considerable congressional experience. While only 46, he landed on Capitol Hill when he was 30, upsetting an incumbent Democrat in 1982 to capture the Ohio 12th Congressional District, which centers on Columbus.

Mr. Kasich, of Westerville, was the only Republican in the country that year able to knock off an incumbent Democrat.

His congressional voting pattern has been reliably conservative, except a 1994 vote to ban assault weapons.

His focus, however, has been on controlling the deficit, angering even some of his fellow Republicans with his repeated attacks on corporate welfare and defense projects such as the B-2 bomber.

He knows more about the budget process than anyone in Washington and he is more passionate, Mr. Luntz said. The passion comes from the inside rather than a political consultant.

As Budget Committee chairman, Mr. Kasich played a leading role in shaping the 1997 budget deal that, in combination with a booming economy, was seen as pulling the federal government out of deficit spending.

I've been able to prove I can bend steel, he said when asked why he should be considered for the presidency.

But others say he overstates his role, that the current budget surpluses come more from a strong economy than legislative craftsmanship.

My impression is that he has done a good job in forcing certain elements of the population to bite bullets, but it would be an exaggeration to say he has bent steel, said Donald Robinson, government professor at Smith College, Northampton, Mass.

Of the 10 likely GOP presidential candidates, Mr. Kasich continues to be bunched with Steve Forbes and former Tennessee Gov. Lamar Alexander at a meager 1 percent or 2 percent in the polls, far behind Texas Gov. George W. Bush and former Labor Secretary Elizabeth Dole.

But longtime Kasich friends say his relentless spirit has helped him overcome similar odds before.

When he first ran for the Ohio General Assembly in 1978, the press and establishment dismissed him as an asterisk, said Gordon Zacks, a Columbus industrialist and Kasich fund-raiser.

Michael Colley, former chairman of the Ohio Republican Party, also remembers the 1978 race, recalling Mr. Kasich as a brash, young candidate.

To win his race, Mr. Colley said, Mr. Kasich knocked on the door of nearly everybody in the district.

Mr. Kasich views himself as a man of the people running for president.

He grew up the son of a mailman outside Pittsburgh in McKees Rocks, Pa. Earlier this year in Iowa, Mr. Kasich proudly went on a tour of bowling alleys to chat with voters.

When John goes into a bowling alley, he is very much at home there. It is not a show, Mr. Gillespie said.

Mr. Kasich also talks about religion  a lot.

His parents were killed by a drunken driver in 1987 when their car pulled out from a fast-food restaurant.

Mr. Colley, an attorney, said there is nothing phony about his religion.

I represented him at that time and watched a change in John. He became more thoughtful, more caring, more helpful to other people, Mr. Colley said.

Other friends agree he has been devout ever since and point to the Bible-study groups he leads on Capitol Hill.

He told the schoolchildren who came to visit him in Washington that they have a permanent friend in the guy who made us. It's very important to think about that.

Mr. Kasich, who recently wrote a book about volunteering called Courage is Contagious, also talks about members of a community helping each other.

If a family down the street needs help, maybe you need to put your nose in that a little bit, he says.

Mr. Kasich's style in Congress, however, still is viewed by many as too prone to hotheadedness and, in some cases, hot-dogging.

He has energy, he has intelligence and I think he has compassion. On the other hand, I think he needs to have an open mind to opinions different from his, said Democratic Rep. Ted Strickland, a fellow member of the Ohio delegation.

Before he is ready to be president, he may need some further life experiences, Mr. Strickland, of Lucasville, said.

Somehow, however, the subject always comes back to his energy.

Working a crowd of 200 Republicans in Newport, N.H., he shuns the podium, walking between tables to make his points, frequently extending his arms to gesture to the audience.

Even when he stops to listen to a question, his body has a hard time staying at ease.

His shoulders move, his eyes blink and he rolls his lips as he waits to gather in what the audience has to say and spring forth with a response.

Conscious of his frenetic pace, he says at another point, I'm talking real fast, I know.

For Mr. Kasich, the strategy now is to pour his famous energy into New Hampshire and Iowa, the two key states early in the primary season that can spring a long-shot candidacy to life or leave it dead.

Everybody is low in the polls except for Bush and Elizabeth Dole, Mr. Gillespie said.

And even with those two, he said, a lot of their high polling numbers are based on name ID.